The present invention relates to the field of metabolic research, in particular the discovery of compounds effective for reducing body mass and useful for treating obesity-related diseases and disorders. The obesity-related diseases or disorders envisioned to be treated by the methods of the invention include, but are not limited to, hyperlipidemia, atherosclerosis, diabetes, and hypertension.
The following discussion is intended to facilitate the understanding of the invention, but is not intended nor admitted to be prior art to the invention.
Obesity is a public health problem that is serious, widespread, and increasing. In the United States, 20 percent of the population is obese; in Europe, a slightly lower percentage is obese (Friedman (2000) Nature 404:632-634). Obesity is associated with increased risk of hypertension, cardiovascular disease, diabetes, and cancer as well as respiratory complications and osteoarthritis (Kopelman (2000) Nature 404:635-643). Even modest weight loss ameliorates these associated conditions.
While still acknowledging that lifestyle factors including environment, diet, age and exercise play a role in obesity, twin studies, analyses of familial aggregation, and adoption studies all indicate that obesity is largely the result of genetic factors (Barsh et al (2000) Nature 404:644-651). In agreement with these studies, is the fact that an increasing number of obesity-related genes are being identified. Some of the more extensively studied genes include those encoding leptin (ob) and its receptor (db), pro-opiomelanocortin (Pomc), melanocortin-4-receptor (Mc4r), agouti protein (Ay), carboxypeptidase E (fat), 5-hydroxytryptamine receptor 2C (Htr2c), nescient basic helix-loop-helix 2 (Nhlh2), prohormone convertase 1 IPCSK1), and tubby protein (tubby) (rev""d in Barsh et al (2000) Nature 404:644-651).
The instant invention is based on the discovery that portions of the full length OBG3 polypeptide, termed OBG3 polypeptide fragments or gOBG3 polypeptide fragments, have unexpected effects in vitro and in vivo, including utility for weight reduction, prevention of weight gain, and control of blood glucose levels in humans and other mammals. These unexpected effects of OBG3 or gOBG3 polypeptide fragment administration in mammals also include reduction of elevated free fatty acid levels caused by administration of epinephrine, i.v. injection of xe2x80x9cintralipidxe2x80x9d, or administration of a high fat test meal, as well as increased fatty acid oxidation in muscle cells, and weight reduction in mammals consuming a high fat/high sucrose diet. These effects are unexpected and surprising given that administration of full-length OBG3 polypeptide typically has no effect in vivo or in vitro. To the extent that any effect is observed following administration of full-length OBG3 polypeptide, the levels of full-length OBG3 polypeptide required for an effect render it unfeasible as a potential treatment for humans at this time. In contrast, the OBG3 and gOBG3 polypeptide fragments of the invention are radically more effective and thus can be provided at levels that are feasible for treatments in humans.
Thus, the invention is drawn to OBG3 and gOBG3 polypeptide fragments, polynucleotides encoding said OBG3 and gOBG3 polypeptide fragments, vectors comprising said OBG3 and gOBG3 polynucleotides, and cells recombinant for said OBG3 and gOBG3 polynucleotides, as well as to pharmaceutical and physiologically acceptable compositions comprising said OBG3 and gOBG3 polypeptide fragments and methods of administering said OBG3 and gOBG3 pharmaceutical and physiologically acceptable compositions in order to reduce body weight or to treat obesity-related diseases and disorders. Assays for identifying agonists and antagonists of obesity-related activity are also part of the invention.
In a first aspect, the invention features a purified, isolated, or recombinant OBG3 or gOBG3 polypeptide fragment that that has significantly greater activity than a full-length OBG3 polypeptide, wherein said activity is selected from the group consisting of lipid partitioning, lipid metabolism, and insulin-like activity. In preferred embodiments, said polypeptide fragment comprises, consists essentially of, or consists of, at least 6 and not more than 238 consecutive amino acids of SEQ ID NO:6 or at least 6 and not more than 241 consecutive amino acids of SEQ ID NO:2 or SEQ ID NO:4. In other preferred embodiments, said polypeptide fragment comprises an amino acid sequence at least 70%, 75%, 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% identical to the corresponding consecutive amino acids of SEQ ID NO:6, SEQ ID NO:2 or SEQ ID NO:4.
In other highly preferred embodiments, said polypeptide fragment comprises, consists essentially of, or consists of, a purified, isolated, or recombinant gOBG3 fragment. Preferably, said gOBG3 polypeptide fragment comprises, consists essentially of, or consists of, at least 6 consecutive amino acids of amino acids 88 to 244 of SEQ ID NO:6 or at least 6 consecutive amino acids of amino acids 91 to 247 of SEQ ID NO:2 or SEQ ID NO:4. Alternatively, said gOBG3 fragment comprises, consists essentially of, or consists of, an amino acid sequence at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% identical to the corresponding amino acids 88 to 244 of SEQ ID NO:6 or at least 75% identical to amino acids 91 to 247 of SEQ ID NO:2 or SEQ ID NO:4.
In a further preferred embodiment, the OBG3 or gOBG3 polypeptide fragment is able to lower circulating (either blood, serum or plasma) levels (concentration) of: (i) free fatty acids, (ii) glucose, and/or (iii) triglycerides. Further preferred polypeptide fragments demonstrating free fatty acid level lowering activity, glucose level lowering activity, and/or triglyceride level lowering activity, have an activity that is significantly greater than full length OBG3 at the same molar concentration, have a greater than transient activity and/or have a sustained activity.
Further preferred OBG3 or gOBG3 polypeptide fragments are those that significantly stimulate muscle lipid or free fatty acid oxidation as compared to full length OBG3 polypeptides at the same molar concentration. Further preferred OBG3 or gOBG3 polypeptide fragments are those that cause C2C12 cells differentiated in the presence of said fragments to undergo at least 10%, 20%, 30% , 35%, or 40% more oleate oxidation as compared to untreated cells or cells treated with full length OBG3.
Further preferred OBG3 or gOBG3 polypeptide fragments are those that are at least 30% more efficient than full length OBG3 at increasing leptin uptake in a liver cell line (preferably BPRCL mouse liver cells (ATCC CRL-2217)).
Further preferred OBG3 or gOBG3 polypeptide fragments are those that significantly reduce the postprandial increase in plasma free fatty acids, particularly following a high fat meal.
Further preferred OBG3 or gOBG3 polypeptide fragments are those that significantly reduce or eliminate ketone body production, particularly following a high fat meal.
Further preferred OBG3 or gOBG3 polypeptide fragments are those that increase glucose uptake in skeletal muscle cells.
Further preferred OBG3 or gOBG3 polypeptide fragments are those that increase glucose uptake in adipose cells.
Further preferred OBG3 or gOBG3 polypeptide fragments are those that increase glucose uptake in neuronal cells.
Further preferred OBG3 or gOBG3 polypeptide fragments are those that increase glucose uptake in red blood cells.
Further preferred OBG3 or gOBG3 polypeptide fragments are those that increase glucose uptake in the brain.
Further preferred OBG3 or gOBG3 polypeptide fragments are those that significantly reduce the postprandial increase in plasma glucose following a meal, particularly a high carbohydrate meal.
Further preferred OBG3 or gOBG3 polypeptide fragments are those that significantly prevent the postprandial increase in plasma glucose following a meal, particularly a high fat or a high carbohydrate meal.
Further preferred OBG3 or gOBG3 polypeptide fragments are those that improve insulin sensitivity.
Further preferred OBG3 or gOBG3 polypeptide fragments are those that form multimers (e.g., heteromultimers or homomultimers) in vitro and/or in vivo. Preferred multimers are homodimers or homotrimers. Other preferred multimers are homomultimers comprising at least 4, 6, 8, 9, 10 or 12 OBG3 or gOBG3 polypeptide fragment subunits. Other preferred mulimers are hetero multimers comprising a OBG3 or gOBG3 polypeptide fragment of the invention.
Further preferred embodiments include heterologous polypeptides comprising an OBG3 or gOBG3 polypeptide fragment of the invention.
In a second aspect, the invention features a purified, isolated, or recombinant polynucleotide encoding said OBG3 polypeptide fragment described in the first aspect, or the complement thereof. In further embodiments the polynucleotides are DNA, RNA, DNA/RNA hybrids, single-stranded, and double-stranded.
In a third aspect, the invention features a recombinant vector comprising, consisting essentially of, or consisting of, said polynucleotide described in the second aspect.
In a fourth aspect, the invention features a recombinant cell comprising, consisting essentially of, or consisting of, said recombinant vector described in the third aspect. A further embodiment includes a host cell recombinant for a polynucleotide of the invention.
In a fifth aspect, the invention features a pharmaceutical or physiologically acceptable composition comprising, consisting essentially of, or consisting of, said OBG3 or gOBG3 polypeptidefragment described in the first aspect and, alternatively, a pharmaceutical or physiologically acceptable diluent.
In a sixth aspect, the invention features a method of reducing body mass comprising providing or administering to individuals in need of reducing body mass said pharmaceutical or physiologically acceptable composition described in the fifth aspect.
In preferred embodiments, the identification of said individuals in need of reducing body mass to be treated with said pharmaceutical or physiologically acceptable composition comprises genotyping OBG3 single nucleotide polymorphisms (SNPs) or measuring OBG3 or gOBG3 polypeptide or mRNA levels in clinical samples from said individuals. Preferably, said clinical samples are selected from the group consisting of plasma, urine, and saliva. Preferably, an OBG3 or gOBG3 polypeptide fragment of the present invention is administered to an individual with at least a 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, or 100% reduction in blood, serum or plasma levels of full length OBG3 or the naturally proteolytically cleaved OBG3 fragment as compared to healthy, non-obese patients.
In a seventh aspect, the invention features a method of preventing or treating an obesity-related disease or disorder comprising providing or administering to an individual in need of such treatment said pharmaceutical or physiologically acceptable composition described in the fifth aspect. In preferred embodiments, the identification of said individuals in need of such treatment to be treated with said pharmaceutical or physiologically acceptable composition comprises genotyping OBG3 single nucleotide polymorphisms (SNPs) or measuring OBG3 or gOBG3 polypeptide or mRNA levels in clinical samples from said individuals. Preferably, said clinical samples are selected from the group consisting of blood, serum, plasma, urine, and saliva. Preferably, said obesity-related disease or disorder is selected from the group consisting of obesity, insulin resistance, atherosclerosis, atheromatous disease, heart disease, hypertension, stroke, Syndrome X, Noninsulin Dependent Diabetes Mellitus (NIDDM, or Type II diabetes) and Insulin Dependent Diabetes Mellitus (IDDM or Type I diabetes). Diabetes-related complications to be treated by the methods of the invention include microangiopathic lesions, ocular lesions, retinopathy, neuropathy, and renal lesions. Heart disease includes, but is not limited to, cardiac insufficiency, coronary insufficiency, and high blood pressure. Other obesity-related disorders to be treated by compounds of the invention include hyperlipidemia and hyperuricemia. Yet other obesity-related diseases or disorders of the invention include cachexia, wasting, AIDS-related weight loss, anorexia, and bulimia. In preferred embodiments, said individual is a mammal, preferably a human.
In related aspects, embodiments of the present invention includes methods of causing or inducing a desired biological response in an individual comprising the steps of: providing or administering to an individual a composition comprising an OBG3 or gOBG3 polypeptide fragment, wherein said biological response is selected from the group consisting of:
(a) lowering circulating (either blood, serum, or plasma) levels (concentration) of free fatty acids;
(b) lowering circulating (either blood, serum or plasma) levels (concentration) of glucose;
(c) lowering circulating (either blood, serum or plasma) levels (concentration) of triglycerides;
(d) stimulating muscle lipid or free fatty acid oxidation;
(c) increasing leptin uptake in the liver or liver cells;
(e) reducing the postprandial increase in plasma free fatty acids, particularly following a high fat meal; and,
(f) reducing or eliminating ketone body production, particularly following a high fat meal;
(g) increasing tissue sensitivity to insulin, particularly muscle, adipose, liver or brain, and further wherein said biological response is significantly greater than, or at least 10%, 20%, 30%, 35%, or 40% greater than, the biological response caused or induced by a full length OBG3 polypeptide at the same molar concentration; or alternatively wherein said biological response is greater than a transient response; or alternatively wherein said biological response is sustained. In farther preferred embodiments, the present invention of said pharmaceutical or physiologically acceptable composition can be used as a method to control blood glucose in some persons with Noninsulin Dependent Diabetes Mellitus (NIDDM, Type II diabetes) in combination with insulin therapy.
In further preferred embodiments, the present invention of said pharmaceutical or physiologically acceptable composition can be used as a method to control blood glucose in some persons with Insulin Dependent Diabetes Mellitus (IDDM, Type I diabetes) in combination with insulin therapy.
In further preferred embodiments, the present invention of said pharmaceutical or physiologically acceptable composition can be used as a method to control body weight in some persons with Noninsulin Dependent Diabetes Mellitus (NIDDM, Type II diabetes) in combination with insulin therapy.
In further preferred embodiments, the present invention of said pharmaceutical or physiologically acceptable composition can be used as a method to control body weight in some persons with Insulin Dependent Diabetes Mellitus (IDDM, Type I diabetes) in combination with insulin therapy.
In further preferred embodiments, the present invention of said pharmaceutical or physiologically acceptable composition can be used as a method to control blood glucose in some persons with Noninsulin Dependent Diabetes Mellitus (NIDDM, Type II diabetes) alone, without combination of insulin therapy.
In further preferred embodiments, the present invention of said pharmaceutical or physiologically acceptable composition can be used as a method to control blood glucose in some persons with Insulin Dependent Diabetes Mellitus (IDDM, Type I diabetes) alone, without combination of insulin therapy.
In further preferred embodiments, the present invention of said pharmaceutical or physiologically acceptable composition can be used as a method to control body weight in some persons with Noninsulin Dependent Diabetes Mellitus (NIDDM, Type II diabetes) alone, without combination of insulin therapy.
In further preferred embodiments, the present invention of said pharmaceutical or physiologically acceptable composition can be used as a method to control body weight in some persons with Insulin Dependent Diabetes Mellitus (IDDM, Type I diabetes) alone, without combination of insulin therapy.
In a further preferred embodiment, the present invention may be used in complementary therapy of NIDDM patients to improve their weight or glucose control in combination with an oral insulin secretagogue or an insulin sensitising agent. Preferably, the oral insulin secretagogue is 1,1-dimethyl-2-(2-morpholino phenyl)guanidine fumarate (BTS67582) or a sulphonylurea selected from tolbutamide, tolazamide, chlorpropamide, glibenclamide, glimepiride, glipizide and glidazide. Preferably, the insulin sensitising agent is selected from metformin, ciglitazone, troglitazone and pioglitazone.
The present invention further provides a method of improving the body weight or glucose control of NIDDM patients alone, without an oral insulin secretagogue or an insulin sensitising agent.
In a further preferred embodiment, the present invention may be used in complementary therapy of IDDM patients to improve their weight or glucose control in combination with an oral insulin secretagogue or an insulin sensitising agent. Preferably, the oral insulin secretagogue is 1,1-dimethyl-2-(2-morpholino phenyl)guanidine fumarate (BTS67582) or a sulphonylurea selected from tolbutamide, tolazamide, chlorpropamide, glibenclamide, glimepiride, glipizide and glidazide. Preferably, the insulin sensitising agent is selected from metformin, ciglitazone, troglitazone and pioglitazone.
The present invention further provides a method of improving the body weight or glucose control of IDDM patients alone, without an oral insulin secretagogue or an insulin sensitising agent.
In a further preferred embodiment, the present invention may be administered either concomitantly or concurrently, with the oral insulin secretagogue or insulin sensitising agent for example in the form of separate dosage units to be used simultaneously, separately or sequentially (either before or after the secretagogue or either before or after the sensitising agent). Accordingly, the present invention further provides for a composition of pharmaceutical or physiologically acceptable composition and an oral insulin secretagogue or insulin sensitising agent as a combined preparation for simultaneous, separate or sequential use for the improvement of body weight or glucose control in NIDDM or IDDM patients.
In further preferred embodiments, the present invention of said pharmaceutical or physiologically acceptable composition further provides a method for the use as an insulin sensitiser.
In further preferred embodiments, the present invention of said pharmaceutical or physiologically acceptable composition can be used as a method to improve insulin sensitivity in some persons with Noninsulin Dependent Diabetes Mellitus (NIDDM, Type II diabetes) in combination with insulin therapy.
In further preferred embodiments, the present invention of said pharmaceutical or physiologically acceptable composition can be used as a method to improve insulin sensitivity in some persons with Insulin Dependent Diabetes Mellitus (IDDM, Type I diabetes) in combination with insulin therapy.
In further preferred embodiments, the present invention of said pharmaceutical or physiologically acceptable composition can be used as a method to improve insulin sensitivity in some persons with Noninsulin Dependent Diabetes Mellitus (NIDDM, Type II diabetes) without insulin therapy.
In an eighth aspect, the invention features a method of making the OBG3 polypeptide fragment described in the first aspect, wherein said method is selected from the group consisting of: proteolytic cleavage, recombinant methodology and artificial synthesis.
In a ninth aspect, the present invention provides a method of making a recombinant OBG3 or gOBG3 polypeptide fragment or a full-length OBG3 polypeptide, the method comprising providing a transgenic, non-human mammal whose milk contains said recombinant OBG3 or gOBG3 polypeptide fragment or full-length protein, and purifying said recombinant OBG3 or gOBG3 polypeptide fragment or said full-length OBG3 polypeptide from the milk of said non-human mammal. In one embodiment, said non-human mammal is a cow, goat, sheep, rabbit, or mouse. In another embodiment, the method comprises purifying a recombinant full-length OBG3 polypeptide from said milk, and further comprises cleaving said protein in vitro to obtain a desired OBG3 or gOBG3 polypeptide fragment.
In a tenth aspect, the invention features a use of the polypeptide described in the first aspect for treatment of obesity-related diseases and disorders and/or reducing or increasing body mass. Preferably, said obesity-related diseases and disorders are selected from the group consisting of obesity, insulin resistance, atherosclerosis, atheromatous disease, heart disease, hypertension, stroke, Syndrome X, Noninsulin Dependent Diabetes Mellitus (NIDDM, or Type II diabetes) and Insulin Dependent Diabetes Mellitus (IDDM or Type I diabetes). Diabetes-related complications to be treated by the methods of the invention include microangiopathic lesions, ocular lesions, retinopathy, neuropathy, and renal lesions. Heart disease includes, but is not limited to, cardiac insufficiency, coronary insufficiency, and high blood pressure. Other obesity-related disorders to be treated by compounds of the invention include hyperlipidemia and hyperuricemia. Yet other obesity-related diseases or disorders of the invention include cachexia, wasting, AIDS-related weight loss, anorexia, and bulimia.
In an eleventh aspect, the invention features a use of the polypeptide described in the first aspect for the preparation of a medicament for the treatment of obesity-related diseases and disorders and/or for reducing body mass. Preferably, said obesity-related disease or disorder is selected from the group consisting of obesity, insulin resistance, atherosclerosis, atheromatous disease, heart disease, hypertension, stroke, Syndrome X, Noninsulin Dependent Diabetes Mellitus (NIDDM, or Type II diabetes) and Insulin Dependent Diabetes Mellitus (IDDM or Type I diabetes). Diabetes-related complications to be treated by the methods of the invention include microangiopathic lesions, ocular lesions, retinopathy, neuropathy, and renal lesions. Heart disease includes, but is not limited to, cardiac insufficiency, coronary insufficiency, and high blood pressure. Other obesity-related disorders to be treated by compounds of the invention include hyperlipidemia and hyperuricemia. Yet other obesity-related diseases or disorders of the invention include cachexia, wasting, AIDS-related weight loss, anorexia, and bulimia. In preferred embodiments, said individual is a mammal, preferably a human.
In a twelfth aspect, the invention provides a polypeptide of the first aspect of the invention, or a composition of the fifth aspect of the invention, for use in a method of treatment of the human or animal body.
In a thirteenth aspect, the invention features methods of reducing body weight comprising providing to an individual said pharmaceutical or physiologically acceptable composition described in the fifth aspect, or the polypeptide described in the first aspect. Where the reduction of body weight is practiced for cosmetic purposes, the individual has a BMI of at least 20 and no more than 25. In embodiments for the treatment of obesity, the individual may have a BMI of at least 20. One embodiment for the treatment of obesity provides for the treatment of individuals with BMI values of at least 25. Another embodiment for the treatment of obesity provides for the treatment of individuals with BMI values of at least 30. Yet another embodiment provides for the treatment of individuals with BMI values of at least 40. Alternatively, for increasing the body weight of an individual, the BMI value should be at least 15 and no more than 20.
In a fourteenth aspect, the invention features the pharmaceutical or physiologically acceptable composition described in the fifth aspect for reducing body mass and/or for treatment or prevention of obesity-related diseases or disorders. Preferably, said obesity-related disease or disorder is selected from the group consisting of obesity, insulin resistance, atherosclerosis, atheromatous disease, heart disease, hypertension, stroke, Syndrome X, Noninsulin Dependent Diabetes Mellitus (NIDDM, or Type II diabetes) and Insulin Dependent Diabetes Mellitus (IDDM or Type I diabetes). Diabetes-related complications to be treated by the methods of the invention include microangiopathic lesions, ocular lesions, retinopathy, neuropathy, and renal lesions. Heart disease includes, but is not limited to, cardiac insufficiency, coronary insufficiency, and high blood pressure. Other obesity-related disorders to be treated by compounds of the invention include hyperlipidemia and hyperuricemia. Yet other obesity-related diseases or disorders of the invention include cachexia, wasting, AIDS-related weight loss, anorexia, and bulimia. In preferred embodiments, said individual is a mammal, preferably a human. In preferred embodiments, the identification of said individuals to be treated with said pharmaceutical or physiologically acceptable composition comprises genotyping OBG3 single nucleotide polymorphisms (SNPs) or measuring OBG3 or gOBG3 polypeptide or mRNA levels in clinical samples from said individuals. Preferably, said clinical samples are selected from the group consisting of blood, serum, plasma, urine, and saliva.
In a fifteenth aspect, the invention features the pharmaceutical or physiologically acceptable composition described in the fifth aspect for reducing body weight for cosmetic reasons.
In a sixteenth aspect, the OBG3 or OBG3 polypeptide fragments are the invention features methods treating insulin resistance comprising providing to an individual said pharmaceutical or physiologically acceptable composition described in the fifth aspect, or the polypeptide described in the first aspect.
In a preferred aspect of the methods above and disclosed herein, the amount of OBG3 or gOBG3 polypeptide fragment or polynucleotide administered to an individual is sufficient to bring circulating (blood, serum, or plasma) levels (concentration) of OBG3 polypeptides to their normal levels (levels in non-obese individuals). xe2x80x9cNormal levelsxe2x80x9d may be specified as the total concentration of all circulating OBG3 polypeptides (full length OBG3 and fragments thereof) or the concentration of all circulating proteolytically cleaved OBG3 polypeptides only.